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ERP2U Power Supply Design Guide, V2.31
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6.9 Redundancy
The power sub-system may have different levels of redundancy depending upon the availability requirements of
the system. The Required, Recommended, and Optional items are broken down here. To be redundant each
item must be in the hot swap power supply module.
STATUS
Required
The power sub-system shall have redundancy of the main power converters for the power factor correction stage
and the main +12V output.
STATUS
Recommended
It is recommended the power sub-system have redundancy for the following items, however, depending upon the
system availability requirements, these items may be non-redundant.
It is recommended to have redundancy for the output or’ing devices, fans, AC bridge, output capacitors, -12V
converter, and 5VSB converter.
STATUS
Optional
It is optional to have redundancy for the AC EMI filter components, 3.3V output converter, and 5V output
converter.
6.10 Hot Swap Requirements
STATUS
Required
The power supply modules shall be hot swappable. Hot swapping a power supply is the process of inserting and
extracting a power supply from an operating power system. During this process the output voltages shall remain
within the limits specified in
Table 20 with the capacitive load specified Table 23. The hot swap test must be
conducted when the sub-system is operating under both static and dynamic conditions. The sub-system shall not
exceed the maximum inrush current as specified in section
5.8. The power supply can be hot swapped by the
following methods:
•
•
AC connecting separately to each module. Up to two power supplies may be on a single AC power source.
Extraction: The AC power will be disconnected from the power supply first and then the power supply is
extracted from the sub-system. This could occur in standby mode or powered on mode. Insertion: The
module is inserted into the cage and then AC power will be connected to the power supply module.
For power modules with AC docking at the same time as DC. Extraction: The module is extracted from the
cage and both AC and DC disconnect at the same time. This could occur in standby or power on mode. No
damage or arcing shall occur to the DC or AC contacts which could cause damage. Insertion: The AC and
DC connect at the same time as the module is inserted into the cage. No damage to the connector contacts
shall occur. The module may power on or come up into standby mode.
Many variations of the above are possible. Supplies need to be compatible with these different variations
depending upon the sub-system construction. In general, a failed (off by internal latch or external control) supply